Strainer



p 2, 1969 A. HARVI/XNEK ETAL 3,464,558

STRAINER Filed June 8, 1967 3,464,558 STRAINER Adolf Harvt'mek and Vaclav Chalupnik, Brno, Czechoslovakia, assignors to Chepos, Zavody chemickeho a potravinarskeho strojirenstvi, oborovy podnik, Brno, Czechoslovakia Filed June 8, 1967, Ser. No. 644,633 Claims priority, application Czechoslovakia, June 23, 1966, 4,194/66 Int. Cl. E02b /08, 5/06 U.S. Cl. 210-159 5 Claims ABSTRACT OF THE DISCLOSURE A strainer for removing floating debris from water running in a channel including a grating of inclined bars whose top ends are arcuately bent to form a downwardly concave bight of the grating, the grating having a frame mounted on a driven shaft centered in the bight and supported on the channel banks. Chains trained over sprockets on the driven shaft and on an idler shaft near the bottom end of the grating carry rakes whose teeth project through the gaps between the grating bars while the teeth move upward between the sprockets and about the drive shaft.

BACKGROUND OF THE INVENTION This invention relates to strainers and more particularly to the strainers suitable for removing floating debris from water in the supply channel of a water wheel or turbine.

In its more specific aspects, the invention is concerned with the cleaning of the water supply for saw mills and paper mills which draw water for their power requirements from rivers on which logs are floated to the mill. Such rivers usually carry relatively large amounts of debris which tend to clog conventional strainers.

An object of the invention is the provision of a selfcleaning strainer which also permits the recovery of the floating debris.

SUMMARY OF THE INVENTION The strainer of the invention has a frame and a plurality of elongated bars mounted on the frame in substantially parallel relationship and defining elongated gaps therebetween. Each bar has a substantially straight portion and an arcuate terminal portion. The bars jointly constitute a grating, and the terminal portions constitute a bight portion of the grating.

Two sprockets are rotatably mounted on the frame, one of the sprockets being arranged in the bight portion of the grating and spaced from the other sprocket longitudinally of the grating bars. The two strands of a continuous chain trained over the sprockets are respectively remote from and near the bars. One of the sprockets is driven in a direction to move the near stand toward the sprocket in the grating bight.

Teeth are arranged on the chain in several groups and are spacedly aligned in each group transversely of the direction of chain movement. While moving on the near strand of the chain, and while moving about the sprocket in the grating bight, the teeth engage the gaps between grating bars and project beyound the grating so as to sweep accumulated debris from the grating and over the bight portion.

The sprocket in the bight portion of the grating is fixedly mounted on a drive shaft rotatably secured to the grating frame and supported in two bearings on the banks of the channel while the straight bar portions are immersed in the channel. The debris brought up over the bight portion is thus readily collected and removed.

nited States Patent O Patented Sept. 2, 1969 Other features and many of the attendant advantages of this invention will be readily appreciated as the same becomes better understood by reference to the following detailed description when considered in connection with the accompanying drawing.

BRIEF DESCRIPTION OF THE DRAWING In the drawing:

FIG. 1 shows a strainer of the invention in side elevational section on the line II in FIG. 2; and

FIG. 2 shows the strainer of FIG. 1 in plan view.

DESCRIPTION OF THE PREFERRED EMBODIMENT Referring now to the drawing in detail, there is seen the water supply channel 1 of a power plant in which water flows in the direction of the arrow. Pillow blocks 2 on the two banks of the river are provided with bearings 3 in which a drive shaft 4 is journaled. The shaft is normally driven clockwise, as viewed in FIG. 1, by a nonillustrated electric motor. The axial portion of the shaft 4 between the bearings 3 carries two fixed sprockets 5 and two brackets 6 which are freely rotatable on the shaft, only one sprocket and one bracket being shown in FIG. 1.

The brackets 6 are attached to a U-shaped frame 7 which is obliquely inclined in the channel 1. Brackets 8 on the bottom end of the frame 7 rotatably support a shaft 9 on which two sprockets 10 are axially spaced. Two link chains 11 are trained over the sprockets 5, 10

and are axially connected by four rakes 12 and four guide rollers 14. The teeth 13 of the rakes are elongated transversely of the direction of chain movement and slope obliquely backward from the chain relative to that direction.

The guide rollers 14 have axially spaced circumferential ribs and are rotatably mounted between the chains 11 closely adjacent respective rakes and behind the associated rakes relative to the direction of chain movement. The ribs of the rollers 14 are aligned with the teeth 13 of the associated rakes 12, as is best seen in FIG. 2, and each rib and the aligned tooth 13 engage a gap between spaced, flat bars 15 which are mounted on the bottom of the frame 7 to form a grating. As is best seen in FIG. 1, the terminal top portions of the grating bars 15 are bent in a circular arc approximately about the axis of the shaft 4 so that the shaft is centered in the bight of the grating formed by the terminal bar portions. The free ends of the bars 15 are arranged above a trough 16 which extends across the channel 1 from bank to bank.

The lower ends of the bars 15 and of the frame 7 are supported on a bar 20 of L-shaped cross section fixedly arranged at the bottom of the channel 1, and are protected by approximately triangular reinforcements 17 against damage by rocks and similar heavy objects rolling along the channel bottom under the pressure of the flowing water. Hooks 18 on the lower end of the frame 7 are attached to a chain 19, only partly shown in the drawing, and connected to a winch above the channel so that the strainer may be lifted from the channel for inspection or repair by pivoting it on the shaft 4.

When the shaft 4 rotates, the rake 13 downward on the remote strands of the chains 11 and upward on the strands near the grating bars 15. The teeth 13 engage the gaps between the bars 15 while they travel upward along the straight bar portions and while they travel about the shaft 4. Debris 21 held against the face of the grating by the flowing water is moved upward by the projecting ends of the teeth along the flat grating face until it is raised from the water, is then moved about the bight portion of the grating above the water level, and ultimately left on the free ends of the bars 15 to be pushed over the ends 3 of the bars 15 and into the trough 16 by the next batch of debris.

The bars 15 are of rectangular cross section and present their narrow faces to the flowing water. They can be defiected transversely by pieces of debris wedging in a gap between adjacent bars. The resulting narrowing of the adjacent gaps would cause the teeth 13 of a rake 12 to be caught, whereby the strainer could be severely damaged. The guide rollers 14 prevent undue deflection of the bars 15. Their sturdy ribs which penetrate into the gaps between the bars 15 tend to dislodge particles of debris. Moreover, they force the bars 15 apart into their proper positions so that even heavy wood particles are crushed between adjacent bars, and damage to the rakes 12 is safely avoided. The rollers 14 are rotated by frictional engagement with the frame 7 while they travel on the near strand of the chains 11.

The chains 11 and sprockets 5, 10 are located behind the grating bars 15 in the direction of water flow and are thereby protected against fouling by floating debris.

The debris is drained of most adhering water while moving over the bars 15 above the water level in the channel 1. It can be burned under boilers after a short drying period. In heavily contaminated waters, a belt conveyor has been found convenient for removing the collected debris from the trough 16.

We claim:

1. A strainer comprising, in combination:

(a) a frame;

(b) a plurality of elongated bars mounted on said frame in substantially parallel relationship and defining elongated gaps therebetween,

(1) each bar having a substantially straight portion and an arcuate terminal portion,

(2) said bars jointly constituting a grating, and said terminal portions constituting a bight portion of said grating;

(c) two sprockets rotably mounted on said frame, one of said sprockets being arranged in said bight ortion and spaced from the other sprocket longitudinally of said bars;

(d) a continuous chain trained over said sprockets,

said chain having two strands extending longitudinally of said bars and being respectively near said bars and remote from said bars;

(e) drive means for rotating said sprockets in a direction to move said near strand from said other sprocket toward said one sprocket;

(f) a plurality of groups of teeth on said chain,

(1) the teeth of each group being spacedly aligned transversely of the direction of chain movement,

(2) said teeth while moving on said near strand and about said one sprocket respectively engag ing said gaps and projecting therefrom in a direction away from said chain; and

(g) a plurality of guide rollers, each roller being mounted on said chain for rotation about an axis transverse of the direction of chain movement, said roller being formed with a plurality of axially spaced circumferential ribs, an axial portion of said roller frictionally engaging said frame during movement of the roller on said near strand for rotation of the roller, and said ribs thereof respectively engaging said gaps for maintaining the spacing of said bars.

2. A strainer as set forth in claim 1, wherein said drive means include a shaft, said one sprocket being fixedly mounted on said shaft, said shaft being rotatably secured to said frame, the strainer further comprising bearing means for supporting the two axial ends of said shaft on the banks of a channel while said straight portions of said bars are immersed in said channel, and said bight portion is located above said shaft.

3. A strainer as set forth in claim 1, wherein the teeth of each group are integrally connected to constitute a rake member.

4. A strainer as set forth in claim 1, further comprising means for swinging said frame about said shaft.

5. A strainer as set forth in claim 1, wherein each guide roller is mounted on said chain closely adjacent an associated group of said teeth and behind the associated group in the direction of chain movement, said teeth being elongated obliquely backward relative to said direction and away from said chain.

References Cited UNITED STATES PATENTS 1,435,770 11/1922 Welser 2l0158 2,823,802 2/1958 Massey 210159 FOREIGN PATENTS 508,424 12/1'954 Canada.

REUBEN FRIEDMAN, Primary Examiner T. A. GRANGER, Assistant Examiner 

